Acoustic Source Term interpolation in Hybrid Aeroacoustic simulation of human phonation

We use a hybrid aeroacoustic approach that relies on an incompressible flow simulation resolving relevant turbulent scales. Based on the flow results, we compute the acoustic source terms on the flow grid and perform a conservative interpolation to the acoustic grid, on which we solve the perturbed convective wave equation to obtain the acoustic field. This conservative transformation of the acoustic sources from the flow grid to the acoustic grid is a crucial step to allow coarse acoustic grids without reducing accuracy. An advanced cut-volume-cell approach, guaranteeing high accuracy both for regions where the flow grid is finer and for regions where it is coarser than the acoustic grid, is employed. In this framework, the radial basis function method is incorporated to compute spatial derivatives of the flow data as necessary in the computation of the acoustic sources. The simulations demonstrate the applicability of the cut-volume-cell interpolation method to obtain an accurate transfer of the acoustic sources from the flow grid to the acoustic grid. The acoustic results changed very slightly even for a reduction of elements in the source region of more than 10 times compared to the initial acoustic grid, leading to a strong reduction in CPU-time.